Device for flow-through ultraviolet light decontamination of microbial contaminants

ABSTRACT

A device for administering a fluid includes a housing that holds a sterilization cassette having a shell, a fluid chamber, and a light transmitting window. An input directs fluid into the chamber. A light source is positioned to direct ultraviolet or other light through the window into the fluid chamber at an intensity sufficient to kill or render non-reproducible at least one species of a microorganism in the fluid while the fluid is in the chamber. An outlet receives fluid from the cassette and directs the fluid to a destination. The fluid is substantially uniformly exposed to the light while in the chamber. The cassette and light source are contained in a housing that prevents light from escaping the housing.

RELATED APPLICATIONS AND CLAIM OF PRIORITY

This patent document is a continuation-in-part of, and claims priorityto, U.S. patent application Ser. No. 12/820,603 filed Jun. 22, 2010,which claims priority to U.S. Provisional Patent Application No.61/269,270 filed Jun. 23, 2009. The disclosures of each priorityapplication are incorporated herein by reference in its entirety.

BACKGROUND

This document describes methods and devices that help prevent infectionsassociated with the infusion or ingestion of fluids into the body.

An intravenous catheter is a hollow tube implanted through the skin fortemporary or semi-permanent residence in a vein. It is used for infusionof various fluids including blood or blood products, for the withdrawalof blood, or to provide access to the circulation for other diagnosticor therapeutic purposes. Similar catheters may be inserted into arteriesor other sterile internal structures for similar purposes. At times anyof these catheters may be inserted across other internal body surfaces,including mucosa of the sinuses, oro-pharynx, gastrointestinal tract,genitourinary system, eye conjunctivae, etc. for similar or analogouspurposes.

Most often these catheters are inserted into internal regions orstructures that are sterile (i.e. devoid of infectious microorganisms).Because these catheters traverse the skin (or analogous body surfaces),they disrupt a crucial barrier preventing the entry of bacteria andother infectious microorganisms from the external environment intosterile regions inside the body. Indeed, such catheters are well knownto represent a major source of infections in humans receiving medicalcare.

Two general mechanisms account for most infections caused by theinsertion and continued presence of intravascular catheters, namely:

-   -   entry of infectious microorganisms through the skin opening        around the exterior of the catheter, permitting them to colonize        the catheter's exterior surface, and giving them direct access        to subsurface tissues and deeper structures where they may cause        infection; and    -   entry of infectious microorganisms, through opening in the fluid        circuit connections and junctions, into the interior regions of        the fluid circuit, including the lumen of the tubing and the        inner surface of the catheter. These microorganisms contaminate        the ostensibly sterile fluid, and are carried through the fluid        circuit into the sterile interior of the body, causing infection        in the blood stream or other structures at the downstream end of        the catheter (so-called “intra-luminal infections”).

The intravenous fluid circuit is the path of fluid flow from a syringeor fluid bag, through tubing, into the lumen of the intravenous catheterinserted into the body, and then into a blood vessel. This fluid pathmay include multiple tubing connections and ports. It is imperative thatthis intraluminal route remain sterile, to avoid introducing infectiouspathogens into the circulation.

The catheter is sterilized before use, and routine catheter insertioninto the patient utilizes procedures that are designed to maintainsterility. The tubing, ports and connectors upstream of the catheterconnection in that fluid infusion circuit, as well as the solutions andmedications infused through that circuit (“infusates”) are presterilizedand connected so as to create and sustain a closed, sterile intraluminalenvironment throughout the circuit and catheter.

Conventional techniques have been developed to maintain that sterilityevery time the closed circuit is broken or entered for the infusion ofadditional fluids or medications, withdrawal of blood, or the attachmentof additional circuits, ports, tubing, fluid bags, or devices.Nevertheless, every port and connection in the fluid circuit representsa potential site for the entry of infectious microorganisms.

Whenever a connection in the closed circuit is broken or a sealed portis removed, sterile interior surfaces of the circuit are exposed to theexternal environment. When so exposed, those sterile interior surfacesmay become contaminated with infectious microorganisms, leading tointraluminal contamination and catheter colonization. Despite efforts toprevent these problems, utilizing optimized design of the fluid circuitcomponents, and intensive education and training in preferred methodsfor sterile accessing of the fluid circuit, intraluminal contaminationand infection remain a substantial problem in clinical medicine.

Once the fluid or the sterile internal surfaces of the catheter fluidpath become contaminated with infectious microorganisms, it becomesextremely difficult to re-establish a sterile environment. Bacteria canbecome lodged within the interstices of the non-smooth surfacemicro-environment of commonly used medical plastics. Furthermore, andmost critically, many bacteria secrete a biofilm during growth, whichprotects and covers the bacteria, rendering them virtually impervious toin situ mechanical, antiseptic and antibiotic eradication measures. Inpractical terms, once the fluid circuit becomes contaminated, it must beassumed that intraluminal surfaces of the fluid circuit may harboradherent bacteria that cannot be removed.

Several approaches have been utilized to address actual or suspectedcatheter infections. The most direct is the removal of the catheter andits associated tubing and fluid bags, with the insertion of a newcatheter, typically at another site.

An alternative but less effective method is the removal and replacementof all of the tubing and fluid path components upstream from thecatheter, without removal of the catheter itself, in the (often vain)hope that although one or more of the circuit components may becolonized, the catheter itself has been spared.

Yet another approach is to insert a guide wire through the lumen of thecatheter into the vein, remove the catheter over the guide wire, andthen insert a new catheter over the guide wire into the same vessellocation. This approach is sometimes successful. However, it is obviousthat the guide wire can collect infectious microorganisms resident onthe inner surface of the colonized tubing or catheter, and transfer themto the new catheter, thereby perpetuating rather than eliminating theunwanted colonization.

Antibiotics or antifungal medications have been infused through acontaminated catheter to kill the contaminating microorganisms. Thisapproach has met with limited success most often because of the presenceof microbial biofilm on the intraluminal surface of the catheter andother fluid circuit components. In principle, antiseptic solutions mightalso be used for decontamination of the inner surface of an intravenouscatheter, but they are generally not suitable or safe for intravenousinfusions at the concentrations needed for this decontamination process.

Another approach is the use of a filter inserted into the fluid path toblock the passage of infectious microorganisms downstream of the filter,preventing catheter contamination and intravascular infection. Suchfilters do not block the passage of all infectious microorganisms, orall of their toxic products, and they do not address any contaminationalready present downstream of the filter.

U.S. Pat. No. 6,461,569 to Boudreaux discloses a device designed toeradicate infection on the internal surface of an indwellingintravascular catheter. The device utilizes an ultraviolet (UV) lightsource emitting microbicidal light in the UV-C spectrum. The lightsource is attached to a fiberoptic bundle that is inserted through thelumen of the intravenous fluid circuit and advanced to the site ofpresumed infection or bacterial colonization on the inner surface of anintravenous catheter. Irradiation of the bacteria with sufficientintensity and duration of UV light of appropriate wavelength can killbacteria or render them incapable of proliferation. However, that devicedoes not prevent the initial colonization of the catheter's innersurface, and does not block the infusion of infectious microorganismsinto the patient. Furthermore, the use of this device breaks the closedfluid circuit, and therefore creates its own additional risk ofmicrobial contamination of the fluid circuit.

Methods have been described to prevent colonization of the catheter withinfectious microorganisms by depositing an antiseptic or antibioticcompound on the surface of the catheter, or within the structure orinterstices of the catheter wall. These compounds may diffuse from thecatheter wall into the adjacent infusate, blood or body fluid, wherethey exert their antimicrobial actions. In other arrangements, thecompounds are chemically linked to the surface structure of thecatheter, and directly interact with the infectious microorganisms insuch a manner as to prevent adhesion, proliferation, or survival. Manydifferent specific compounds and salts have been used; examples includesilver salts, various antibiotics, and chlorhexidine. Clinicalexperience suggests that such specially treated catheters have modestbut limited efficacy in preventing colonization by infectiousmicroorganisms. The development of biofilm may render these compoundsineffective for their intended purpose.

In addition, problems exist with water supplies, as many supplies arelocated in remote locations that can become contaminated withmicroorganisms.

The presence of infectious microorganisms in the luminal fluid is likelyto remain an inevitable consequence of the usage of intravascularcatheters and similar devices for fluid infusion and blood withdrawal incontemporary medical practice. What is needed, therefore, is a devicethat will reduce or eliminate the risk that viable infectiousmicroorganisms that may appear in the fluid circuit from being delivereddownstream to contaminate the sterile catheter or cause infection of thesystemic circulation. It is also desirable to provide a device thatreduces or eliminates microorganisms from fluids that will be ingestedinto the body, such as water spigots or faucets.

SUMMARY

In an embodiment, a device for administering a fluid includes a housingin which a sterilization cassette is seated. The sterilization cassetteincludes a shell, a fluid chamber, and an light transmitting window. Thewindow may be able to pass one or more types of light, such as visiblelight or ultraviolet light. An inlet is connected to a first portion ofthe sterilization cassette and configured to receive a fluid from asource and deliver the fluid to the chamber. A light source, such as anultraviolet light source or a visible light source, is positioned todirect ultraviolet light through the window into the fluid chamber. Anoutlet is connected to a second portion of the sterilization cassette sothat it may receive the fluid from the cassette and direct the fluid toa destination. The cassette includes channels so that the fluid mixeswithin the chamber. The light source directs light into the chamber atan intensity sufficient to kill or render non-reproducible at least onespecies of a microorganism in the fluid while the fluid is in thechamber.

Optionally, the device may also include a tube, such as an intravascularcatheter, having a distal tip and a proximal end. The proximal end maybe connected to the outlet tube and configured to receive the fluid fromthe outlet tube and direct the fluid through the distal tip.Alternatively, the inlet tube may include a gasket configured to beattached to a water supply. With either option, a one-way valve may beconnected to the outlet tube and positioned to prevent re-entry of thefluid into the outlet tube after the fluid passes through the valve.Either option also may include a flow regulator that limits the flowrate of the fluid into the chamber.

In some embodiments, the light source may include a housing containing,a power supply, a lamp structure that is powered by the power supply,and a positioning structure to seat the cassette in the housing. Thehousing may be sealed to prevent light from the lamp structure frombeing emitted outside of the housing when the cassette is seated insideof the housing. A sensor may detect whether the cassette is properlyseated in the housing, so that a circuit connected to the sensor thatcauses the light source to remain off unless the cassette is properlyseated in the housing. In addition, a sensor may detect whether thehousing is closed to prevent ultraviolet light from escaping thehousing, so that a circuit connected to the sensor causes the lightsource to remain off unless the housing is closed. Also, a sensor maydetect whether the light is of at least a predetermined intensity in thechamber, and it may trigger a signal when the light is on but the sensordetermines that the light is below the predetermined intensity for aperiod of time. The signal may be an alarm signal, a signal to keep thelight off, or another type of signal. The signal may control a flowregulator that ensures that no fluid flows into the cassette if an alarmcondition exists.

Optionally, the light source may emit light at multiple wavelengths inthe ultraviolet spectrum. Also optionally, an ultravioletlight-reflective material may be positioned to reflect the light backinto the chamber after the light passes from the window through thechamber. Also optionally, one or more interior surfaces of the chambermay be coated with a photocatalytic material that, through oxidation oranother process, kills microbes when the coating is exposed to an energysource (such as visible light of sufficient intensity) and contacts themicrobes.

Optionally, the housing may include an opening that accepts a downstreamend of the outlet tube so that, when inserted through the opening andinto the chamber, the downstream end will be exposed to the light.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustration of a simplified fluid circuit for the infusionof fluid into a vein, according to the prior art.

FIG. 2 is an illustration showing examples of elements of a fluidsterilization circuit.

FIG. 3 is an illustration of examples of features of a sterilizationcassette.

FIG. 4 illustrates additional examples of features of a sterilizationcassette.

FIG. 5 illustrates additional examples of features of a sterilizationcassette.

FIG. 6 is a front view of an example of a light source assembly.

FIG. 7 illustrates a sterilization cassette seated in a housing with alight source.

FIG. 8 is a front view of an example of a light source assembly withwearable component.

FIG. 9 is a side view of an example of a light source assembly withwearable component.

FIG. 10 is a block diagram of an example electronic circuit for a lightsource assembly.

FIG. 11 illustrates two sterilization cassettes seated in a housing witha light source.

FIG. 12 illustrates a housing configured to receive and sterilize an endstructure of a tube.

FIG. 13 illustrates example features of an alternate sterilizationcassette.

DETAILED DESCRIPTION

Before the present systems, devices and methods are described, it is tobe understood that this disclosure is not limited to the particularsystems, devices and methods described, as these may vary. It is also tobe understood that the terminology used in the description is for thepurpose of describing the particular versions or embodiments only, andis not intended to limit the scope.

It must also be noted that as used herein and in the appended claims,the singular forms “a,” “an,” and “the” include plural references unlessthe context clearly dictates otherwise. Unless defined otherwise, alltechnical and scientific terms used herein have the same meanings ascommonly understood by one of ordinary skill in the art. Although anymethods, materials, and devices similar or equivalent to those describedherein can be used in the practice or testing of embodiments, thepreferred methods, materials, and devices are now described. Allpublications mentioned herein are incorporated by reference. As usedherein, the term “comprising” means “including, but not limited to.”

Fluid, such as infused through an intravascular (IV) fluid circuit intoa vein, is prepared in a sterile fashion and is intended to remainsterile as it flows through the fluid circuit. However, this fluid maybe contaminated with microorganisms during preparation or storage, or bythe presence of microorganisms that may enter the fluid circuit throughvarious connections or ports. Such organisms may subsequently colonizethe fluid circuit tubing, or the IV catheter, leading to continuedcontamination of the infused fluid and possible infection of thecatheter site and the blood stream.

We disclose a device, with its defined components, that prevents orreduces the delivery, into the blood circulation, of viable infectiousmicroorganisms that may be carried in fluid (“infusate”) flowing in afluid infusion circuit such as an IV circuit. The ability to reduce oreliminate the presence of infectious microorganisms in the infusatethereby minimizes or prevents the possibility of microbial colonizationof the downstream IV catheter, thereby mitigating or preventing catheterinfection, and subsequent systemic infection. In other embodiments, thedevice may reduce, remove or eliminate microorganisms from ingestiblewater. In such embodiments, the device may reduce, remove or eliminatemicroorganisms from ingestible water by killing one or more species ofmicroorganisms or rendering one or more of the species incapable ofreproduction.

This device functions by illuminating the fluid, and infectiousmicroorganisms contained therein, as the fluid flows through a specificregion of the fluid circuit, with light, such as bactericidal doses ofultraviolet light of wavelength 240-365 nm (“UV-C”). Such light is knownto have potent capacity to kill or inactivate a wide range of bacteria,fungi and viruses. One mechanism for this action of UV-C light is thechemical modification of DNA by the production of dimers of pyrimidinenucleotides present in the organisms' DNA, thereby inhibiting DNAreplication. Other mechanisms may be used. Without such replication,these microorganisms cannot proliferate and, hence, cannot causeclinical illness. Optionally, light of multiple wavelengths in the UV-Crange may be used. Optionally, light in the visible spectrum (e.g.,about 390 to about 700 nm) may be used, optionally in combination with aphotocatalytic coating on the interior of the device.

FIG. 1 illustrates a conventional IV fluid circuit 40 and a contiguousdownstream IV catheter 50 inserted into a region of the body such as avein 60, according to the prior art. IV fluid enters a delivery tube 55or 58 from a syringe 75 and/or a fluid reservoir 78. Access into thevein 60 is created by an IV catheter 50 that passes through the skinsurface and subcutaneous tissues, and enters the vein 60 with thedownstream (distal) tip 56 of the catheter securely within the vein. Theupstream (proximal) end 57 of the IV catheter typically has one or moreluer lock connections 68 allowing for secure, water-tight and generallybacteriostatic connection to tubing 58 or another device via acomplementary luer lock connector. Additional pieces of tubing may beinterconnected by additional luer lock connectors 66.

Referring again to FIG. 1, the IV fluid circuit typically includestubing 55, 58 that is fluidly connected to the upstream end 57 of the IVcatheter, through which fluid (sometimes referred to in this document as“infusate”) flows, driven by hand pressure, gravity or a pump, from asource such as syringe 75 or fluid reservoir bag 78 into the vein orother internal structure where the downstream end 56 of the IV catheter50 may reside. Connections between segments or components of the IVfluid circuit and between the IV catheter fluid circuit and the IVcatheter are typically accomplished by luer-lock type reversibleconnections 66, 68, although other methods for connection are also used.Additional sites where the system may be entered include injection portswith open ends, or comprising flexible membranes punctured by needles orother needle-less devices; open-ended segments of tubing; or stopcocks79 covered by a removable cap or other device. All of these sitesrepresent sites where infectious microorganisms can enter the fluidcircuit to contaminate the IV fluid. In the prior art, it has been knownto attempt decontamination of fluid in a tube by directing light 70 atthe tube. However, this process is not effective and typically cannot beperformed in a patient room without exposing the patient to potentiallyharmful ultraviolet rays.

FIG. 2 illustrates an example of a device 140 for administering a fluidwith UV or other light-based decontamination. As with FIG. 1, the device140 in FIG. 2 includes an IV catheter 150 for insertion into a vein,160. IV fluid enters a delivery channel 155 from an injection cartridge175, fluid reservoir bag 178 or other source such as one connected via avalve 179 at the end of the tube 155. The distal tip 156 of the cathetermay be placed securely within the vein 160.

A sterilization cassette 130 may be positioned to receive fluid from thefluid source via an input tube 132 and direct the fluid to the cathetervia an outlet tube 134. The input tube 132 may be connected to the fluiddelivery tube 155 via a luer lock connection 166 or other connectiondevice. Similarly, the outlet tube 134 may be connected to the catheter150 via a luer lock connection or other connection device 168. Thus,fluid from the source may pass through the input tube 132, enter thecassette 130, and then follow the outlet tube 134 to the catheter 150.Optionally, the connection device 168 may include a one-way valve thatprevents fluid from re-entering the outlet tube (and thus the cassette)after it passes out from the outlet tube and through the connectiondevice 168. In an alternative embodiment (not shown) the downstreamconnection 168 is eliminated, and the sterilization cassette's outlettube 134 and the IV catheter 150 are a single, unified structure, and aone-way valve is substituted for the downstream connection 168.Optionally, the fluid delivery channel 155 may include one or moreimpellers that form at least part of a fluid turbine 181 that turns asfluid is gravity-fed through the input tube. The fluid turbine may beconnected to a generator 183 that generates power in response to theturning of the turbine. The power may be used to power the device.

Optionally, the input tube may be fluidly connected to a flow regulatorthat ensures that fluid does not enter the cassette at a flow rate thatis higher than a predetermined flow rate. The predetermined flow ratewill be one that is desirable to ensure that fluid passing through thecassette is exposed to UV light for at least a predetermined minimumexposure time. The cassette 130 may be seated in a housing 120 that alsoholds an ultraviolet light source 125 that is powered by a power supply127 (such as a battery or an external wire) and which directs light intothe cassette when the cassette is seated in the housing. Irradiation ofthe fluid in the cassette 130 with sufficient intensity and duration ofmicrobicidal ultraviolet light from the light source 125, at one or morewavelengths in the range of 240-365 nm from the UV light source, willcause elimination, or multi-log reduction in the quantity of viableinfectious micro-organisms that may be contained within that fluid.Alternatively, the light source 125 may emit light in the visiblespectrum (i.e., about 390 to about 700 nm). In addition, the interior ofthe light-transmitting window or other interior portion of the cassettemay be coated with a photocatalytic material such as titanium dioxide(TiO₂). Upon exposure to the light, the photocatalytic material may killone or more bacteria or other microbes in the fluid through oxidation oranother process.

Similarly, if the infusate is known to be sterile, or is made sterile atsome alternative sterilization site along fluid path, and if thedownstream tubing and the IV catheter are sterile, and if all potentialdownstream microorganism entry sites are obviated or eliminated (e.g. atthe tubing connection to the upstream end of the catheter), then thefluid delivered downstream into the vein or other sterile structure willremain sterile. Furthermore, under such conditions, the inner surfacesof the downstream tubing and IV catheter will remain free ofcolonization by such infectious microorganisms.

The cassette, housing, and input/outlet tube structure described hereinmay be detached from the catheter circuit and re-used in other circuits.Alternatively, the cassette, housing, and input/outlet tube structuredescribed herein may be discarded after a single use. Alternatively,instead of being used with a catheter structure as shown in FIG. 2, thecassette 130 and housing 120 may be connected to a fluid source toreceive water from an input source such as a valve, spigot, faucet orother delivery mechanism. Water is then passed through the cassette,exposed to UV light and sterilized, and passed through the outlet tubeto a spigot or faucet or into a receptacle.

FIG. 3 illustrates exemplary elements of a cassette 130 that isconnected to the input tube 132 and outlet tube 134. One or moresurfaces of the sterilization cassette comprises a window 234 capable oftransmitting ultraviolet light at one or more wavelengths in the rangeof 240-365 nm. For example, the window 234 may be made of quartz oranother UV-transmissive material. Alternatively or in addition, thewindow may transmit light in the visible spectrum. Optionally, the inlettube 132 may be fluidly connected to a flow regulator 142 and/or afilter 144. The flow regulator 142 may be a pinch valve, a flow controlvalve, a regulator valve, or any other type of flow regulator thatlimits the flow rate of the fluid entering the cassette so that the rateby which fluid passes through the cassette is controlled, thus ensuringthat the fluid is exposed to UV light in the cassette for a desiredperiod of time. Optionally, the flow regulator 142 may be electronicallyconnected to a controller, such as a computer processor or aprogrammable logic controller, that directs the regulator to increase,decrease, stop, and/or start the flow. In one embodiment, the controllermay issue a stop command and/or not permit a start command until the UVlight source is on and/or it determines that the housing is closed, thecassette is properly seated, and/or no alarms are triggered. The flowregulator may be controlled by mechanical operation, by an electricsignal, or by an electromagnetic field. The flow regulator 142 mayinclude shut-off capability, or a separate shut-off valve 500 may beprovided and controlled by the controller. The filter 144 may be acarbon or other filter that filters suspended and/or dissolved solidsfrom the fluid, thus removing particles that may effectively absorb orreflect light if allowed to enter the fluid chamber.

FIG. 4 shows a cut-away view with the window removed to reveal a fluidchamber 133 that is surrounded by a wall structure (i.e., a shell) 131.Optionally, the chamber may include baffles or other protrudingstructures 135 that create and/or extend the path for the flow of fluidthrough the chamber, thus causing turbulence, ensuring that the time inwhich all fluid passes through the chamber is substantially equal andthus allowing for control of the UV light exposure time for at leastsome of the fluid that passes through the chamber. The internal fluidpath within the fluid chamber 133 may be straight, or it may take one ofvarious routes. These various routes are designed and intended to createturbulence and avoid eddies, thereby ensuring adequate mixing ofinfusate so that transit time through the sterilization cassette issubstantially invariate at any given inflow rate, and exposure to UVlight is substantially uniform. For example, the cassette fluid chamber133 may is provided with walls or baffles 135, positioned perpendicularto the surface of the window 234, that create an internal fluid pathwith recursive, preformed channels. In another embodiment, thesterilization cassette internal fluid path has recursive, preformedchannels or similar arrangements, separated by walls or baffles, saidbaffles oriented in a plane parallel to the plane of the first surface.In another embodiment the fluid path is split with walls or baffles intoa group of parallel channels. In another embodiment the fluid pathincludes a spiral. In another embodiment the fluid path includes ahelix. Various other arrangements, and various combinations andpermutations of such arrangements, are possible, and may be used. Allsuch arrangements are included in this disclosure.

FIG. 5 is a cut-away side view showing that a second window 139 may bepositioned on a side of the chamber that is opposite the first window.The second window may pass light out of the chamber so that it isreflected from a reflecting surface of the interior of the housing andback into the fluid chamber 133. Alternatively, the second window 139may instead be a reflecting surface that is positioned to reflect lightback into the chamber.

FIG. 6 shows an optional light source assembly 225 that includes, amongits components, a UV light source 228 that includes an array oflight-emitting diodes (LEDs). Overlying the light-emitting surface ofsome or all of the LEDs may be placed one or more lens or other devicesto direct, filter or collimate the emitted light. Each LED or the LEDarray may include a hermetically sealed housing with lens, heat sink andstandard transistor outline header for electrical connections. Oneembodiment of an LED suitable for this application is an AlGaN/GaN LEDwith power dissipation of 150 mW, 30 mA current with UV output power of0.5 mW at 280 nm. An array consisting of two or more such LEDs can beused, depending upon UV output power requirements and other factors.LEDs of different wavelengths can also be combined in the light source.Other lamps and light source structures are possible.

As shown in FIG. 7, when the sterilization cassette 130 is seated withinthe housing 120, the transmitting window 234 of the sterilizationcassette may be brought in proximity with and aligned to receive lightfrom the light source 228. Light 230, such as UV light that emanatesfrom the light source 228 at one or more wavelengths in the range of240-365 nm, passes through the window 234 and illuminates fluid flowingin the fluid chamber 133 of the sterilization cassette, causingelimination or multi-log reduction in the quantity of viable infectiousmicro-organisms in that fluid. Optionally, if the sterilization cassetteincludes a reflective surface contained on or next to second window 139,or if the cassette includes a second window 139 that is aligned with areflective surface inside of the housing 120, the light 230 may bereflected back from the reflective surface 192 and into the chamber 133.Various interior surfaces of the housing in the area of the light sourcemay also contain UV-reflective material or other reflective to enhancelight delivery to the sterilization cassette.

The inner surface of the housing 120 and the outer surface of thecassette 130 may each contain structures of appropriate shape and designsuch that the sterilization cassette may be positioned and thus seatedsecurely in its operating position in the housing. For example, thehousing may contain one or more depressions or contours, and thecassette may contain corresponding protruding structures or opposingcontours, so that the cassette and housing may be properly positioned tohave matching or interconnecting contours and thus be seated. Thehousing and/or cassette may include one or more pressure sensors,positional sensors, or other sensors to detect whether the cassette isproperly seated. The sensors may be connected to the circuit to preventthe light source from turning on unless the cassette is properly seated,or to actuate an alarm circuit.

One or more sensors 329 may be positioned on the inner surface of thehousing 120 to detect the intensity of light emitted from the lightsource 228 and transmitted through the sterilization cassette. Othersensors (and their associated visible or UV light sources, ifappropriate) may be provided on various surfaces and regions of thelight source housing to monitor for variables such as infusateturbidity, satisfactory positioning of the sterilization cassette,complete closure of the light source housing, and other operatingparameters.

Thus, FIG. 7 shows that light 230 emanating from the LED array 228positioned adjacent to the first window 234 passes through the firstwindow 234 to illuminate fluid within the fluid chamber 133. Any lightnot absorbed or refracted within the fluid chamber 133 passes throughthe second window 139 and is reflected back from a reflective material192 positioned on an inner surface of a first piece 129 of the housing120, again traversing the second window 139 to reenter the fluid path.Any light not absorbed or refracted within the fluid chamber 133 willthen pass back through the first window 234, where it may be absorbed,refracted, or reflected by any reflective material it may strike on theinner surface 189 of a second piece 178 of the housing.

Referring now to FIG. 8, the light source assembly may include a lightsource housing 120, and it may optionally include an attachmentcomponent 232 for securing light source housing to a limb or other partof a human body in a wearable form. For example, the attachmentcomponent 232 may include a wearable armband-like device that may besecured to a limb, with a “one size fits all” design, so as to reducetraction on the IV catheter. In another embodiment, not shown, theattachment component may include a flexible sheet with an adhesiveunderside for attachment to a body part or surface of the organism orobject receiving the infusate, and with a surface mounted holder tosecure the light source housing. Optionally, as shown in FIGS. 6 and 8,a cover or lid 236 may be removably or movably secured such as by hinges238 over the light source when the item is not in use (or when thecassette is in the housing). As shown in FIG. 9, the light sourceassembly 225 may include openings in its housing 241, 242 through whichthe inlet tube and outlet tube of the sterilization cassette may pass.Otherwise, the assembly housing may be opaque to UV and/or other lightand thus configured to prevent light from passing out of the housingwhen the UV lamps are powered on. Various surfaces of the housing may becoated, painted or otherwise covered with UV light-absorbing material toprevent escape if UV light from the interior of the light sourcehousing. Flanges may be provided along the surfaces of the first pieceand the second piece, to ensure that no path for the emission of lightexists between the first piece and the second piece. Internal bafflesmay be added or substituted and other arrangements provided to preventexternal emissions of light from the light source.

FIG. 9 also shows that the housing may include one or more output signallights or alarms 233, one or more input buttons 245 for control ofinternal circuitry.

In various embodiments, the light source assembly 225 may include aninternal power supply, connections for external power supplies,monitoring sensors, microprocessor, external input devices, lightsource, alarm circuits and output devices. FIG. 10 is a schematicrepresentation of an embodiment of the electronic circuitry for thelight source assembly. As shown in FIG. 10, the circuit and relatedstructures may include a light source 228 and photosensor 329 thatdetects when the light source is on.

Optionally, the photosensor 329 may send a signal to a metering circuit330 and/or microprocessor 335 that ensure that the light is only on iffluid is flowing through the circuit. Other sensors, such as pressuresensors and/or positional sensors, may send signals to ensure that thelight is only on if the cassette is properly seated and/or the housingis closed and sealed so that light does not escape the housing. Thesystem may accomplish this by allowing the power control 340 to deliverpower to the light source if the fluid is flowing, and optionally onlyif the cassette is properly seated within the housing. The system alsomay include an alarm 233 controlled by a driver 333 to indicate whetherthe device is working properly or not. In addition, an input on-offswitch 245 may control connection of the power and/or a battery 350,battery charging circuit 355 and battery metering circuit 360.Optionally, a removable AC power charger 370 also may be provided. Theprocessor also may control an input flow regulator that stops (or doesnot permit the start of) fluid flow into the cassette if the light isnot on, if the housing is not closed and sealed, if the cassette is notproperly seated, or if an alarm condition is triggered by any of theseor other events.

It may be shown that at any inflow rate, the total transit time throughthe sterilization cassette is a function of the fluid volume of thesterilization cassette, but not, to a first approximation, related tothe route, geometry or length of the fluid path, assuming uniform andcomplete illumination within the sterilization cassette, turbulent flowand complete mixing of fluid within the sterilization cassette. Hencethe fluid volume of the sterilization cassette may be varied toinfluence the exposure time of fluid within the sterilization cassetteto light.

In order to prevent entry of infectious microorganisms into the infusateafter exposure of the infusate to UV-C it may be desired that the IVcatheter fluid circuit remain impervious to microbial entry at allpoints downstream from the sterilization cassette. In one embodiment,the sterilization cassette is attached directly to the downstream IVcatheter under sterile conditions with a luer lock-type connector thatcontains a latch mechanism that creates a non-removable connection,impervious to microbial entry, between the downstream connection of thesterilization chamber and the contiguous IV catheter. In such anembodiment, no additional ports, connectors or connection sites arepermitted or available downstream from this site. In another embodiment,the downstream connection between the sterilization cassette and IVcatheter is sealed, while sterile, with a microbe-impermeable sealant(e.g., cyanoacrylate glue). In another embodiment, the sterilizationcassette and the IV catheter are manufactured as a single integral unit.

The light source described above accommodates a single sterilizationcassette. In an alternative embodiment, as shown in FIG. 11, the lightsource housing 120 may be adapted to accommodate two or moresterilization cassettes 130A, 130B, each containing a first window 234and a second window 139. The sterilization cassettes may be stacked andoriented atop or alongside one another such that light emanating fromthe light source 228 that is not absorbed or refracted as it passesthrough a first sterilization cassette 130B may continue on toilluminate the internal fluid path of a second and any additionalsterilization chambers 130A. After exiting the final sterilizationchamber 130A in such a stack, the light will then encounter thereflective material 192 on the inner surface of a portion 129 of thelight source housing 120. That light will be reflected back through thesuccessive sterilization chambers in reverse order.

Such an arrangement will permit the use of this device for thesimultaneous sterilization of infusates flowing into two or more lumensof a multi-lumen IV catheter. In an alternative embodiment, the LEDarray and the interior space of the sterilization cassette housing maybe enlarged so that two or more sterilization cassettes may beaccommodated side by side.

In an alternate embodiment, exemplary elements of which are shown inFIG. 12, the housing of the light source assembly 225 may include anopening 260 through which the downstream end and associated gaskets 266or other structures of a sterilization cassette outlet tube or otherfluid transmitting tube may be inserted. When the housing's cover 236 isclosed and the light 228 is powered on, the end of the tube 134 and endstructures 266 may be decontaminated.

In another embodiment, the first piece 129 and the second piece 178 ofthe light source housing 120 are manufactured as a single unitarystructure, with an opening on one surface of the light source housing,permitting access to an interior space of the light source housing,where the light source is positioned. In this embodiment thesterilization cassette 130 may be modified as shown FIG. 13 to includean opaque panel 352 attached to a side of the sterilization cassetteshell, with the attached tubing 134, 132 passing through the panel 352.The panel 352 will be of such shape as to fit and lodge snugly withinthe aforementioned opening on the surface of the light source housingwhen the sterilization cassette shell is inserted into the interiorspace of the light source housing. When the sterilization cassette shellis positioned inside the light source housing such that the panel 352 issnugly lodged within the opening on the surface of the light sourcehousing, the first window and (if provided) the second window of thesterilization cassette will be positioned in the correct orientation andposition relative to the LED array and the reflective material.

In another embodiment of this device, the LED or LED array is notprovided, and microbicidal light in one or more wavelengths of 240-350nm is provided by light source consisting of a mercury vapor UV lamp. Inone arrangement of this embodiment, the mercury vapor lamp and itsassociated power supply are not integral with the light source assembly.Rather, light emitted by the mercury vapor lamp may be captured by aUV-transmitting fiber-optic cable, and is delivered by that fiber-opticcable to the sterilization cassette within the interior space of thelight source housing where it illuminates the internal fluid path of thesterilization cassette through the first window. The mercury vapor lampand power supply may be attached to an IV pole or similar supportproximate to the light source housing. In an alternative embodiment, themercury vapor lamp and its associated power supply are miniaturized, andare integral with the wearable light source housing. UV light from themercury vapor lamp may be delivered to the sterilization cassette bymeans of mirrors, lenses and/or UV transmitting fiber-optic cable.

This disclosure makes repeated reference to veins, IV catheters, andprocedures and infections related to those structures and devices. Inanalogous applications, a catheter may be inserted into an artery, orany of various other internal sterile body structures or regions for theinfusion of fluid or the removal of blood or other internal fluids. Itshould be understood that when reference is made in this disclosure tothe use of this invention for purposes pertaining to veins or IVcatheters or infusions, and any related infection issues, that thisinvention also discloses use of this invention for analogousintra-arterial applications, and for analogous applications where acatheter is inserted through the skin or body surfaces, or body orificeof any organism into another internal sterile structure or region ofthat organism for the infusion of fluid or the removal of blood or otherinternal fluids. This disclosure also includes the use of this deviceand the application of this method for sterilization of flowing orstatic fluids not infused into biologic systems.

Furthermore, the term “fluid” as used in this disclosure should beunderstood to include not only water or simple salt or sugar solutions,but also any liquid that may be administered to a human, other animal,plant, or other organism. The liquid may be ingested or otherwise enterinto the organism, including natural body fluids, and includes but isnot limited to those fluids that may consist of, or contain,medications, proteins, nutrients, blood, blood products, chemotherapy,chemicals, as well as natural body fluids, and any other appropriatecompound.

All combinations and permutations of the various embodiments describedin this document are included in this invention, as well as otherembodiments that may be known or deduced by those skilled in the art orthis invention.

By way of example, urine is commonly drained from the urinary bladderinto a collecting bag by means of a catheter and its associated tubing.Urine in the collecting bag may become contaminated with infectiousorganisms; those organisms may be introduced back into the bladder ifurine flows retrograde through the tubing into the bladder, such as whenthe collecting bag is elevated above bladder level. In one embodiment ofthis invention, the sterilization cassette is connected into the urinarydrainage circuit and the connections are sealed, preferably beforecatheter insertion into the bladder. A flow-limiting valve is includedin the urinary circuit to prevent urine flow at a rate beyond thesterilization capacity of the device. In one method of usage of thisinvention for this application, the sterilization cassette is insertedinto the light source housing according to the principles of thisinvention, and the light source is activated continuously, prior toinsertion of catheter into the bladder. By such a process thepossibility of bacterial colonization of the urinary bladder byretrograde flow of urine from a contaminated urinary collection bag maybe eliminated.

Another embodiment may use devices disclosed herein for sterilizing tapwater or other liquids that may be contaminated with infectiousorganisms. In such an embodiment the attached tubing of thesterilization cassette may include a flow-limiting valve to prevent thefluid flow rate from exceeding the sterilization capacity of the device.The upstream end of the attached tubing may be provided with a gasketsuch as a screw or clamp connector allowing it to be attached to afaucet or other water supply. The sterilization cassette may bepre-sterilized and hermetically sealed. When ready for use, it may beunwrapped and inserted into the light source housing, which is thenswitched on. The upstream end of the attached tubing is connected to thewater supply and the water supply is turned on. After usage, thesterilization cassette may be discarded to avoid bacterial growth fromthe downstream tubing.

Various embodiments may be used with indwelling IV catheters,particularly those such as central venous catheters, PICC lines,tunneled central lines, hemodialysis catheters, and the like, that mayremain in place for more than a few hours. This device can also be used,if necessary with adaptation by one skilled in the art, with indwellingintra-arterial lines, and other catheters that may be used to deliversterile fluids into the interior of the body, including into the centralnervous system, chest or abdominal cavity, and to deliver sterile fluidto, or adjacent to, peripheral nerves or to similar structures. It isunderstood that all references to IV catheters in this document alsoinclude reference to these other sites of fluid delivery, and all typesof catheters and similar devices used for such purposes, whether inhumans, other mammals, or in any plant or animal species, or toinanimate objects for similar or analogous purposes.

The sterilization cassette may be provided in a pre-sterilized package.If so, the package may be opened in sterile fashion. The sterilizationcassette, along with the IV catheter and the catheter insertionmaterials and supplies, may be placed in a sterile fashion into thesterile field prepared for IV catheter insertion. In a sterile fashion,the sterilization cassette may be flushed with an appropriate sterilesolution from a sterile syringe attached to the upstream port of thesterilization chamber, and the syringe is left in place. The IV cathetermay be inserted into the vein under sterile conditions, and then flushedin a sterile fashion with an appropriate sterile solution. Thesterilization cassette may then be connected, via irreversible luer lockconnector, to the upstream end of the IV catheter. If needed, a sealant,such as cyanoacrylate glue is applied to this connection to create apermanent bacteriostatic seal. The necessary dressings are applied tothe site of catheter entry into the skin, and the IV catheter is securedto the skin.

The sterilization cassette is positioned in its operating positionwithin the light source housing and the second piece is closed over itand latched. The light source with its associated electronics isactivated, initiating killing of any microorganisms within thesterilization chamber. The syringe is removed from the upstream tubingof the sterilization chamber, and that tubing is connected to the fluidcircuit. Infusate flow is initiated, and the light source remains on atall times. The flow rate, exposure time, and light intensity may beselected to kill and/or render the microorganisms incapable ofreproduction. Such parameters may be selected or predetermined bytesting, depending on the fluid and organisms that will be treated.

Warning lights or other alarms may be activated if battery power fallsbelow preset parameters, allowing the user to replace the battery, or torecharge the battery while the device remains in use. A UV or otherlight detector may monitor light delivery through the sterilizationcassette and initiate appropriate warning signals if the intensity ofthe received light of a desired wavelength or wavelength range fallsbelow acceptable limits. Such a situation might indicate dirt or debrissomewhere in the light path, malposition of the sterilization cassetteor failure of the light source. For example, if a fluid solutionincompatible with UV-C exposure (e.g., blood, platelets, certainmedications), appears in the sterilization chamber, an absorptiondetection mechanism may immediately identify the condition, disable theUV-C light, and activate a warning signal to notify the user that theUV-C light has been disabled. Detectors may identify if the light sourcehousing is not closed properly, or if other facets of device operationare not within operating ranges, and will activate suitable alarms andnecessary safeguards.

It will be appreciated that various of the above-disclosed and otherfeatures and functions, or alternatives thereof, may be desirablycombined into many other different systems or applications. It will alsobe appreciated that various presently unforeseen or unanticipatedalternatives, modifications, variations or improvements therein may besubsequently made by those skilled in the art which are also intended tobe encompassed by the disclosed embodiments.

The invention claimed is:
 1. A device for administering a fluid,comprising: a housing that contains: a sterilization cassette comprisinga shell, a fluid chamber comprising a plurality of channels, and anultraviolet light transmitting window, a portion of an input tubeconnected to a first portion of the sterilization cassette, wherein theinput tube is configured to receive a fluid from a source and deliverthe fluid to the chamber, an ultraviolet light source positioned todirect ultraviolet light through the window into the fluid chamber, anda portion of an outlet tube connected to a second portion of thesterilization cassette and configured to receive the fluid from thecassette, wherein the channels are configured to create turbulence inthe fluid within the chamber, and the ultraviolet light source isconfigured to provide the ultraviolet light at an intensity sufficientto kill or render non-reproducible at least one species of amicroorganism in the fluid while the fluid is within the chamber; achannel that delivers fluid from the source to the cassette; a turbinecomprising one or more impellers positioned within a fluid flow path ofthe channel; a generator that generates electricity in response toactuation of the turbine by fluid moving along the fluid flow path; anda tube having a distal tip and a proximal end, wherein the proximal endis connected to the outlet tube and configured to receive the fluid fromthe outlet tube and direct the fluid through the distal tip.
 2. Thedevice of claim 1, further comprising: a one-way valve connected to theoutlet tube and positioned to prevent re-entry of the fluid into theoutlet tube after the fluid passes through the valve.
 3. The device ofclaim 1, further comprising: a positioning structure configured toproperty position the cassette in the housing; and a sensor configuredto detect whether the cassette is properly seated in the housing; andone or more of the following: a circuit connected to the sensor, whereinthe circuit is configured to prevent the light source from turning onunless the cassette is properly seated within the housing; or an alarmcircuit configured to actuate if the sensor detects that the cassette isnot properly seated in the housing.
 4. The device of claim 1, furthercomprising: an ultraviolet light-reflective material positioned toreflect the light back into the chamber after the light passes from thewindow through the chamber.
 5. The device of claim 1, furthercomprising: a flow regulator; a controller that controls the flowregulator; and a sensor configured to detect one or more conditions;wherein the controller is configured to not permit fluid flow throughthe flow regulator if the sensor detects an alarm condition.
 6. A fluiddelivery system, comprising: a fluid reservoir; a tube having a distaltip and a proximal end; a housing that holds: a sterilization cassettecomprising a shell, a fluid chamber, and a light transmitting window, aninlet, wherein the inlet is configured to receive fluid from thereservoir and deliver the fluid to the chamber, a light sourcepositioned to direct light through the window into the fluid chamber atan intensity sufficient to kill or render non-reproducible at least onespecies of a microorganism in the fluid while the fluid is in thechamber, and an outlet, wherein the outlet is configured to receive thefluid from the cassette and direct the fluid to the proximal end of thecatheter, wherein the sterilization cassette is configured so that thefluid mixes within the chamber in a manner so that the fluid issubstantially uniformly exposed to the light while in the chamber; achannel that delivers fluid from the source to the cassette; a turbinecomprising one or more impellers positioned within a fluid flow path ofthe channel; and a generator that generates electricity in response toactuation of the turbine by fluid moving along the fluid flow path. 7.The system of claim 6, further comprising: a one-way valve connected tothe outlet tube and positioned to prevent re-entry of the fluid into theoutlet tube after the fluid passes through the valve.
 8. The system ofclaim 6, further comprising: a positioning structure configured toproperty position the cassette in the housing; and a sensor configuredto detect whether the cassette is properly seated in the housing; andone or more of the following: a circuit connected to the sensor, whereinthe circuit is configured to prevent the light source from turning onunless the cassette is properly seated within the housing, or an alarmcircuit configured to actuate if the sensor detects that the cassette isnot properly seated in the housing.
 9. The system of claim 6, furthercomprising: an ultraviolet light-reflective material positioned toreflect the light back into the chamber after the light passes from thewindow through the chamber.
 10. The system of claim 6, furthercomprising: a flow regulator; a controller that controls the flowregulator; and a sensor configured to detect one or more conditions;wherein the controller is configured to not permit fluid flow throughthe flow regulator if the sensor detects an alarm condition.
 11. Thesystem of claim 6, further comprising: a photocatalytic coating on aninterior portion of the cassette.
 12. The system of claim 11, whereinthe coating comprises titanium dioxide, and the interior portioncomprises an interior face of the window.
 13. A device for administeringa fluid, comprising: a housing that contains: a sterilization cassettecomprising a shell, a fluid chamber comprising a plurality of channels,and an ultraviolet light transmitting window, wherein the sterilizationcassette is removably seated within the housing; an inlet configured toreceive a fluid from a source and deliver the fluid to the chamber, anultraviolet light source positioned to direct ultraviolet light throughthe window into the fluid chamber, and an outlet configured to receivethe fluid from the cassette and direct the fluid to a destination; achannel that delivers fluid from the source to the cassette; a turbinecomprising one or more impellers positioned within a fluid flow path ofthe channel; a generator that generates electricity in response toactuation of the turbine by fluid moving along the fluid flow path; anda tube having a distal tip and a proximal end, wherein the proximal endis connected to the outlet and configured to receive the fluid from theoutlet and direct the fluid through the distal tip.
 14. The device ofclaim 13, further comprising: a one-way valve connected to the outlettube and positioned to prevent re-entry of the fluid into the outlettube after the fluid passes through the valve.
 15. The device of claim13, further comprising: a positioning structure configured to propertyposition the cassette in the housing; and a sensor configured to detectwhether the cassette is properly seated in the housing; and one or moreof the following: a circuit connected to the sensor, wherein the circuitis configured to prevent the light source from turning on unless thecassette is properly seated within the housing, or an alarm circuitconfigured to actuate if the sensor detects that the cassette is notproperly seated in the housing.
 16. The device of claim 13, furthercomprising: an ultraviolet light-reflective material positioned toreflect the light back into the chamber after the light passes from thewindow through the chamber.
 17. The system of claim 13, furthercomprising: a flow regulator; a controller that controls the flowregulator; and a sensor configured to detect one or more conditions;wherein the controller is configured to not permit fluid flow throughthe flow regulator if the sensor detects an alarm condition.